IN the days before the initials SUV were even thought about, four-wheel-drives were rough, tough and usual shaped liked bricks on wheels.

How times have changed. Take a look at the latest Lexus RX with its razor-edged lines, sweeping curves and aerodynamic tweaks and you are reminded how styling and perceptions have advanced.

Yes, this large five-door may be equipped with all-wheel-drive, but it it's very much today's iteration of luxury transport, effectively replacing the prestige three-box saloon once epitomised by models like the Jaguar XJ and BMW Seven Series.

Yes, the Lexus RX is capable of scrabbling up a dirt track or clawing its way across a muddy field, but I hazard a guess that few owners would contemplate it.

The RX450h+ F Sport we drove has an angrily aggressive nose, tall stance and substantial girth, yet it's a pussy cat to drive with a hushed engine and muted exhaust note (that's when it's not running on electric alone).

Power comes from a 2,487cc four cylinder petrol engine coupled to an electric plug-in hybrid system which together pumps out 304bhp, pretty substantial punch even for a five-seater measuring almost five metres long.

But dynamics and sporty handling isn't where the Lexus majors, though it acquits itself well enough on that score. Refinement, comfort and ease of driving are its chief qualities. Seats (both front and rear) are sumptuously supportive, the fascia is elegant and beautifully made and there's a genuine feeling of occasion about the cabin.

Undoubtedly some will whine about the touchscreen's controls and the ‘nannying' safeguards aimed at accident prevention, but these are features being adopted by a growing number of manufacturers.

While the 461 litre boot isn't massive it's probably large enough for most families' luggage. And we felt there wasn't quite enough space for oddments in the front of the cabin. Clutter must be confined to either the door pockets, smallish central box or the glovebox.

Equipment is as lavish as the price tag suggests with electric seat and steering wheel adjustment, triple zone climate control, 12 speaker audio system, heated steering wheel and hands-free power tailgate are fitted as standard. Mind you, the metallic silver coachwork was a £250 extra.

The 450h gets Lexus's favoured CVT gearbox which, like most continuously variable automatic transmissions, sounds somewhat frenetic when the accelerator is floored - as though the engine is racing. This detracts to some extent from the general refinement of the car.

Acceleration is swift enough with 62mph coming up in under seven seconds. Top speed is 124mph, fast enough for most.

A definite plus is its economy. Even hard driving results in more than 45mpg and a gentle scenic run of 50 miles saw the figure rise to 55mpg - amazing for a luxury family express.